Aqueous dispersion



Patented Jan. 14', 1936 AQUEOUS DISPERSION 1 Jacob Mitchell Fain, Brooklyn, N. Y., assignor, by

assignments, to The Patent and Licensin; Corporation, New York, N. Y., acorporation of Massachusetts No'Drawing. Original application November 21, 1928, Serial No. 321,045. Divided and this application January 24, 1931, Serial No. 511,108

15Claims.

This is a division of my co-pending application Ser. No. 321,045, filed November 21st, 1928.

This invention relates to the art of making aqueous dispersions of bituminous and like substances normally'immiscible with water. Bituminous dispersions as known tothe art at the present time, may be produced by various processes and with the aid of numerous substances functioning as dispersing media to assist in causing subdivision of the bitumen into dispersed particles of more or less fine size. Generally speaking, dispersion may be efiected by at least two distinct types of operations. In one type, the dispersing medium functions to reduce the surface tension of the aqueous medium, this being generally evidenced by its ability to foam so that dispersion takes place largely by virtue of this property, this type of. operation being normally operable within considerable temperature latitudes within which the phases ,are liquid. Under these conditions, only relatively slight mechanical action is necessary to produce the dispersion and generally, no great difliculty is experienced in attaining fine particle size. Soap and soapy materials are among the substances which function in the foregoing manner to produce dispersion, although, of course, other materialscapable'of reducing surface tension of the aqueous medium may be utilized. V

The dispersion products produced under the foregoing conditions and with the aid of the aforenamed emulsifying media are frequently unstable, and particularly when the amount of emulsifying media employed approximates the 35 minimum that will effect a material reduction in I the surface tension, lthe product is unable to maintain the dispersed state upon standing for substantial periods of time-and hence breaks down upon standing. with quantities of the media inexcess of the critical minimum reierred to, the product may be made to maintain its dispersed state for substantial periods of time although, of course, even in such case the introduction of electrolytes and similar 45 influences, are generally sumcient to cause a breaking of the dispersion.

In the other type of operation, the emulsifiers employed operate under conditions influenced largely by the temperature and the viscosity of 50 the aqueous dispersion medium. This type of operation requires carefully controlled temperatures and considerable internal friction in the mass undergoing dispersion with consequent aqueous medium in the production of disper- 55 sions of desirable character. In general, pasteforming powders such as finely divided clays, bentonite and the like, are examples of dispersing media employed in conjunction with this second type of operation. When these materials are thus employed to produce fine sub-division 5 of the dispersed particles, the resultant product will be comparatively stable, not only in it's ability to maintain the dispersed state upon standing for considerable periods of time, but also to the action of most electrolytes.

The object of the present invention is to utilize the advantages incident to the type of operation first above described for the production of dispersionswhich in certain respects, possess the stability characteristic of the prod- 15 ucts formed under the second type of operatingconditions as above described.

Another object of the invention resides in the provision of a method for utilizing materials capable of reducing the surface tension of the m acqueous medium in the production of dispersions, the amount of surface tension reducing material employed being regulated to the minimum necessary to provide, in conjunction with materials falling under the second group, a suiilcient reduction in surface tension to enable'the combined media to disperse bitmnen in a manner characteristic of the first type of operation above described, yet having far greater stability .(so' far as maintaining the dispersed state is so concerned) than is normally possible with such type of operation, the resultant product more nearly resembling in this respect the product produced with far greater quantity of emulsifying agent of the first type of the product made in accordance with the second type of operation.

' Other objects of the invention will hereinafter more fully appear from the following description of the invention.

In carrying out my invention, I may combine 40 with bentonite and/or clay or other colloidal powders capable of formin a paste'or viscous suspension with water, an agent capable of lowering the surface tension of the aqueous medium so as to render the bitumen more readily susceptible to rapid subdivision into fine particles by a comparatively light stirring or agitating action. By thus utilizing an agent for reducing the surface tension of the asphalt, I am enabled to produce dispersions without requiring' a very nice and skflle'd control of the temperature conditions during the operation, and at'thesame time producing a relatively stable product due to the presence therein of the clay, bentonite or other-mineral powder, and without which the product would be comparatively unstable.

In one embodiment of my invention, I have dispersed a relatively soft asphalt of Columbian stock, the asphalt having a melting point of say between 70 and 90 degrees F., by combining about eight parts of bentonite with one part of soap (sodium oleate) in a solution of about 400 parts of water and dispersing therein approximately 1200 parts by weight of the asphalt, the asphalt in hot molten state being added to the bentonite-soap suspension accompanied by a stirring action performed in any suitable equipment designed for the purpose. The final dispersion as thus produced, as will be seen from the figures given, contains approximately 75% of the asphalt, 25% of water, 0.5% bentonite and ie% of soap, the finished dispersion. These amounts of bentonite and soap total to 0.5625% based on the weight of the dispersion, or 0.75% based on the weight of the asphalt. With such a small proportion of the soap, this product, in the absence of the bentonite, would normally be comparatively unstable and standing for any considerable length of time, say a few weeks. Due to the presence of the bentonite, however, this disruption of the product is prevented. On the other hand, it will be apparent to those skilled in the art, that in order to satisfactorily disperse asphalt of such a soft nature with a small amount of material like bentonite, a very careful control of the temperature conditions during the operation would be necessary, but that, in accordance with my invention, the necessity for this control is eliminated due to the function of the soap, the operation thusresembling the dispersion of asphalt with materials like soap, in that the same may be carried on at relatively high temperatures varying over a considerable range, which would ordinarily seriously encumber the operation when using material such as bentonite or the like.

In another embodiment of my invention I may use saponin as the surface tension reducing material in lieu of soap. To produce dispersion with .this material I may combine the same with a paste forming colloid such as bentonite in proportions say of one part of the saponin to say one to about three parts of bentonite. With these proportions'I may produce a stable dispersion of asphalt of the above described character and containing about 70 to 75% of the asphalt, 30 to 25% of water, about A.% saponin, and to bentonite. Here again the combined weight of saponin and bon tonite is not more than 1% by weight of the finished dispersion andalso less than 2% by weight of the asphalt contained in the dispersion.

I may also carry out my invention by combining soap with an aqueous mixture of gelatin in quantities to reduce sufliciently the surface tension of the aqueous medium so as to enable satisfactory dispersion to take place. With this procedure and using approximately two parts of gelatin to each part of soap, the final dispersion may contain approximately 70 to 75% of the bitumen, about soap, gelatin, and the balance water, i. e., about of soap and gelatin combined, based on the weight of the dispersion, or about 1% of soap and gelatin combined, based on the weight of the bitumen contained in the dispersion.

The last named procedure may also becareach based on the weight of in fact, breaks down upon ried out with the substitution of saponin in lieu of the soap, in which event the dispersion produced may contain about saponin, A;% gelatin, the bitumen and water content being approximately the same as that stated. The final product in such case would therefore contain 1.25% of saponin and gelatin combined, based on the weight of the dispersion, or 1.66% based on the weight of the bitumen contained in the dispersion.

It should be understood that in the illustrations hereinabove given, the stability of .the proding not substantially less than 50% by weight' of bitumen and containing a mixture of soluble soap and a mineral powder colloid as the primary emulsifying gent and not less than 25% of water as the continuous phase, said soap and mineral powder colloid being present in a combined amount less than 1% by weight of the dispersion.

2; An aqueous dispersion of bitumen comprising not substantially less than 50% by weight of bitumen and containing a mixture of soluble soap and a mineral powder colloid as the primary emulsifying agent and not less than 25% of water as the continuous phase, said soap and mineral powder colloid being present in a combined amount less than 1% by weight of the bitumen contained m ne dispersion,

3. An aqueous dispersion of bitumen comprising not substantially less than 50% by weight of bitumen and containing a mixture of solublesoap and bentonite as the primary emulsifying agent and not less than 25% of water as the continuous phase, said soap an bentonite being present in a combined amount less than 1% by weight of the bitumen contained in the dispersion.

5: An aqueous dispersion of bitumen comprising not substantially less than 50% by weight ofbitumen and containing a mixture of soluble soap and a mineral powder colloid as a primary emulsifying agent and not less than 25% of water as the continuous phase, said soap being present in an amount less than 1% by weight of the dispersion and said mineral powder colloid being present in an amount less than 1% by weight of the bitumen contained in the dispersion.

6. An aqueous dispersion of bitumen comprising not substantially less than 50% by weight of bitumen and containing a mixture of soluble soap and a mineral powder colloid as the priof water as the continuous phase, said soap being present in an amount less than 1% by weight of the bitumen contained in the dispersion, and said mineral powder colloid being present in an amount less than 1% by weight of the dispersion.

'7. An aqueous dispersion of bitumen comprising not substantially less than'50% by weight of bitumen and containing a mixture of soluble soap and bentonite as the primary emulsifying agent and not less than 25% of water as the continuous phase, said soap being present in an amount less than 1% by weight of the dispersion and said bentonite being present in an amount less than 1% by weight of the bitumen contained in the dispersion.

8. An aqueous dispersion of bitumen comprising not substantially less than by weight of bitumen and containing a mixture of soluble soap and bentonite as the primary emulsifying agent and not less than 25% of water as the continuous phase, said soap being present in an amount less than 1% by weight of the bitumen contained in the dispersion. and said bentonite being present in an amount less" than 1% by weight of the dispersion.

9. An aqueous dispersion of bitumen comprising not substantially less than 50% by weight of bitumen and containing a mixture of soluble soapand a mineral powder colloid as the primary emulsifying agent and not less than 25% of water as the continuous phase, said soap and colloid being present in a, combined amount less than 2% by weight of the dispersion.

10. An aqueous dispersion of bitumen comprising not substantially less than 50% by weight of bitumen and containing a mixture of soluble soap and bentonite as the primary emulsifying agent and not less than 25% of water as the continuous phase, said soap and bentonite being present in a combined amount less than 2% by weight of the dispersion.

11. An aqueous dispersion of bitumen comprising not substantially less than 50% by weight of bitumen and containing not less than 25% by weight of water and containing as the primary emulsifying agent a mixture of less than 1% soap and less than 1% bentonite, both based on the weight of the dispersion.

12. An aqueous dispersion of bitumen comprising not substantially less than 50% by weight of bitumen and containing not less than 25% by weight of water and containing as the primary emulsifying agent a mixture of less than soap and not more than bentonite, both based on the weight of the dispersion.

13. An aqueous dispersion of bitumen comprising not substantially less than 50% by weight of bitumen and containing not less than 25% by weight of water and containing as the primary emulsify ng agent a mixture of less than 1% soap and not more than 1% bentonite, both based on the weight of the dispersion.

14. An aqueous dispersion of bitumen comprising not substantially less than 50% by weight of bitumen and containing not less than 25% by weight of water and containing as the primary emulsifying agent a mixture of soluble soap in an amount less-than 1% by weight of the dispersion and bentonite in an amount less than 1% by weight of the dispersion, but sufficient to maintain the uniformly dispersed state of the product upon standing over considerable periods of time.

15. An aqueous dispersion of bitumen comprising ,not substantially less than 50% by weight of bitumen, not less than 25% by weight of water, and a combination of soap and bentonite as the primary emulsifying agent in an amount -not exceeding 2% by weight of the bitumen contained in the dispersion.

JACOB mTCI-IEIL PAIN. 

